He isn't mean, he's just strict. Mr. Ibsen is the theater director in the first book (Odeum), who is notoriously grumpy, but does an excellent job casting, and directing shows. His work with Jauq Maures at the theater began upon the completion of the building.
It is rumored in the story that Mr. Ibsen's attitude is due to how little Jauq pays him. Aside from his prickly behavior, he is also known for being impatient but direct with his cast. He takes his position seriously at the theater and underneath his rough exterior is a man who is passionate about his work.